Methods of power management and apparatus thereof

• US 20100299545A1
• Filed: 03/31/2010
• Published: 11/25/2010
• Est. Priority Date: 05/20/2009
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: LYU, Young-Ki
• Granted Patent: US 8,245,057 B2
• Time in Patent Office: Days
• US Class Current: 713/322
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: G06F 1/3296 by lowering the supply or operating voltage
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method of power management detects a workload rate of a processor, increases a power level of the processor based on a first value that is an average of the detected workload rate over an up reference time, and decreases the power level of the processor based on a second value that is an average of the detected workload rate over a down reference time. The down reference time may be longer than the up reference time. A power management apparatus includes a processor, a workload detector configured to detect a workload rate of the processor, a power management unit configured to receive the workload rate of the processor and generate a level control signal indicating a power level of the processor, a voltage control unit configured to provide the processor with a supply voltage corresponding to the level control signal, and a clock control unit configured to provide the processor with a clock signal having a frequency corresponding to the level control signal.

Claims

1. A method of power management, comprising:

detecting a workload rate of a processor;

increasing a power level of the processor based on a first value, the first value being an average of the detected workload rate over an up reference time; and

decreasing the power level of the processor based on a second value, the second value being an average of the detected workload rate over a down reference time, the down reference time being longer than the up reference time.

2. The method of claim 1, wherein at least one of increasing the power level of the processor and decreasing the power level of the processor includes:

adjusting a frequency of a clock signal supplied to the processor.

3. The method of claim 2, wherein the at least one of increasing the power level of the processor and decreasing the power level of the processor further includes:

adjusting a supply voltage of the processor.

4. The method of claim 1, further comprising:

decreasing the power level of the processor based on a third value, the third value being an average of the detected workload rate over a static reference time, the static reference time being longer than the down reference time.

5. The method of claim 4, further comprising:

decreasing the power level of the processor based on the second value when the second value is smaller than a down reference value; and

decreasing a power level of the processor based on the third value when the third value is smaller than a static reference value,

wherein the static reference value is greater than the down reference value.

6. The method of claim 1, further comprising:

suspending an operation of the processor until the increased power level or the decreased power level is stabilized.

7. The method of claim 1, wherein detecting the workload rate of the processor includes:

generating a plurality of unit workload rates of the processor consecutively by detecting the workload rate of the processor at intervals of a unit reference time.

8. The method of claim 7, wherein increasing the power level of the processor based on the first value includes:

calculating the first value by averaging m unit workload rates among the plurality of unit workload rates, m being a positive integer; and

increasing the power level of the processor when the first value is greater than an up reference value, and

wherein decreasing the power level of the processor based on the second value includes;

calculating the second value by averaging n unit workload rates among the plurality of unit workload rates, n being a positive integer greater than m; and

decreasing the power level of the processor when the second value is smaller than a down reference value.

9. The method of claim 8, further comprising:

calculating the third value by averaging k unit workload rates, k being a positive integer greater than n; and

decreasing the power level of the processor when the third value is smaller than a static reference value,

wherein the static reference value is greater than the down reference value.

10. The method of claim 7, further comprising:

calculating the first value and the second value by averaging a plurality of weighted unit workload rates, each of the plurality of weighted unit workload rates being generated by multiplying each unit workload rate by a respective weight value.

11. The method of claim 10, further comprising:

multiplying a first unit workload rate of the plurality of unit workload rates by a first weight value; and

multiplying a second unit workload rate of the plurality of unit workload rates by a second weight value,

wherein the first weight value is larger than the second weight value if the first unit workload rate indicates a recent workload rate of the processor than the second unit workload rate.

12. The method of claim 10, further comprising:

decreasing the power level of the processor based on a third value, the third value being an average of the plurality of weighted unit workload rates over a static reference time, the static reference time being longer than the down reference time.

13. The method of claim 1, further comprising:

increasing the power level of the processor to a maximum power level when a desired event occurs, the desired event including an external input.

14. A power management apparatus comprising:

a processor;

a workload detector configured to monitor an operation of the processor and detect a workload rate of the processor;

a power management unit configured to receive the detected workload rate of the processor and generate a level control signal indicating a power level of the processor;

a voltage control unit configured to provide the processor with a supply voltage corresponding to the level control signal; and

a clock control unit configured to provide the processor with a clock signal having a frequency corresponding to the level control signal.

15. The power management apparatus of claim 14, wherein the workload detector detects the workload rate of the processor at intervals of a unit reference time and successively generates a plurality of unit workload rates, and

the power management unit controls the level control signal to increase the power level of the processor based on a first value indicating an average of the workload rates over an up reference time and to decrease the power level of the processor based on a second value indicating an average of the workload rates over an down reference time.

16. The power management apparatus of claim 15, wherein the power management unit comprises:

a calculation unit configured to receive the workload rates from the workload detector and generate a comparison signal indicating the increase or decrease of the power level of the processor.

17. The power management apparatus of claim 16, wherein the calculation unit comprises:

a history unit including a plurality of delay units, each delay unit configured to store a unit workload rate received from a previous delay unit and output the stored unit workload rate to a next delay unit after a desired time;

an amplification unit including a plurality of amplifiers, each of the plurality of amplifiers configured to output an amplified corresponding unit workload rate received from the history buffer;

a summing unit including a plurality of adders, each adder configured to sum an output of corresponding amplifiers, the corresponding amplifiers including each amplifier outputting an amplified unit workload rate to the adder; and

a division unit including a plurality of dividers, each divider configured to divide an output of a given adder by a corresponding sum of gains of corresponding amplifiers, the corresponding amplifiers including each amplifier outputting an amplified unit workload rate to the given adder.